XTR115 and XTR116 are precision 4 to 20-mA, current-loop transmitters for industrial sensor and signal-acquisition systems. The transmitters from Burr-Brown Corp., Tucson, target applications where sensor signals are processed with microcontrollers because electrical power is not available at the sensor site. The sensor signals are amplified, linearized, and transmitted in current form. Current loops are not affected by line resistance. The devices feature low quiescent current, wide-loop supply range, a 5-V regulator for powering external circuitry, precision-voltage reference for sensor excitation, and low span error. A current pin senses current used in external circuitry for accurate control of the output current.